import launch
import launch_ros
from ament_index_python.packages import get_package_share_directory
import os

import launch_ros.parameter_descriptions
def generate_launch_description():
    #获取默认urdf path
    urdf_package_path = get_package_share_directory('fishbot_description')
    default_urdf_path = os.path.join(urdf_package_path,'urdf','first_robot.urdf')

    default_rviz_path = os.path.join(urdf_package_path,'config','display_robot_model.rviz')
    #声明一个URDF目录参数，方便修改
    action_declare_arg_mode_path = launch.actions.DeclareLaunchArgument(
        name='model',
        default_value=str(default_urdf_path),
        description='加载的模型文件路径',
    )
    #启动节点加载  需文件内容
    command_result=launch.substitutions.Command(['xacro ',launch.substitutions.LaunchConfiguration('model')])
    robot_description_value=launch_ros.parameter_descriptions.ParameterValue(command_result,value_type=str)

    action_robot_state_publisher = launch_ros.actions.Node(
        package='robot_state_publisher',
        executable='robot_state_publisher',
        parameters=[{'robot_description':robot_description_value}]
    )
    action_joint_state_publisher = launch_ros.actions.Node(
        package='joint_state_publisher',
        executable='joint_state_publisher',
    )
    action_rviz_node = launch_ros.actions.Node(
        package='rviz2',
        executable='rviz2',
        arguments=['-d',default_rviz_path]
    )
    return launch.LaunchDescription([
        action_declare_arg_mode_path,
        action_robot_state_publisher,
        action_joint_state_publisher,
        action_rviz_node,

    ])